AcelRx Pharmaceuticals announced positive results from a Phase 2 clinical study evaluating the safety and efficacy of its ARX-02 sufentanil NanoTab Breakthrough Pain Management System in the treatment of cancer breakthrough pain in opioid-tolerant patients. This study initially enrolled 42 cancer patients with breakthrough pain. Of those patients, 36 (86%) were successful in titrating to an effective dose of ARX-02 with minimal side effects. In the double-blind, placebo-controlled phase of the study, titrated patients were randomized to receive a blinded sequence of seven doses of ARX-02 and three doses of placebo for use in treating ten distinct breakthrough pain events over the course of a three-week period. The primary endpoint of time-weighted Sum of the Pain Intensity Difference over the first 30 minutes after dosing (SPID-30) was highly statistically significant for ARX-02 compared to placebo (p < 0.001). Additionally, key secondary endpoints demonstrate that ARX-02 achieves rapid onset of analgesic efficacy in this patient population.

Sufentanil is a strong opioid that is approximately 5-10 times more potent than fentanyl, yet has an 80-fold wider safety margin (therapeutic index), as determined in animal studies. The NanoTab is designed to allow rapid uptake of sufentanil following placement under the tongue, maximizing transmucosal drug uptake and limiting the proportion of swallowed drug.